I have currently spray painted 4 coats of primer (Dark Grey by VHT ) on the bottom hull of my sub. Question I was looking to use "Testor Dull Coat" to seal and to make the entire paint job look more uniform.... The reason I choose Dull Coat by Testors was the fact when I applied decals and then use dull coat onto to them they never came lose due to the effects of water.....I always was impressed by that......On the other side of the coin I heard Dull Coat is not water proof....ANY ADVICE IS WELL COME.....